If you always raise or reraise with AA preflop, until all the chips are in the middle, then you are not making any real mistake. There are certain situations, where a slowplay can be higher EV, but if you are new to the game and maybe not all that comfortable postflop, then just take an aggressive action, when you have the nuts. And dont choose silly sizing like making it only 5BB over a 2,5BB open raise. Use the same size, you would use with other
hands, like maybe 3X in position and 4X out of position for a 3-bet.
Postflop AA is really just a hand, and there are no concepts, that apply exclusively to AA. They are all general like value betting,
bluff catching, pot control, hand planning, hand reading and so on and so forth. So the best advice is to simply take the CC 30 day course, if you did not do it already. The only difference is, that AA is almost never a hand, we should consider
bluffing with, since its always at least the best possible one pair hand.
The final and maybe most important advice is about the mental game. You need to accept, that getting drawn out on is part of the game. Just because you are ahead at some point, dont mean, you will always be ahead on the river. This is just part of the game, and it does not really matter, if you have AA, which was the nuts preflop, or maybe you flopped top pair but ended up losing to a flush. In both situations the goal is to not lose more, than you have to, and then simply move on to the next hand without letting it tilt you.